Horror scenes as more than 400 whales strand themselves

RESCUERS trying to save 100 whales who survived one of the country's largest mass strandings are facing a major setback as the refloated whales start heading back into the beach.

Only 100 pilot whales survived after a large pod of 416 stranded on Farewell Spit overnight.

The Department of Conservation Golden Bay operations manager Andrew Lamason said the survivors that had been refloated were now swimming in the wrong direction and headed back into the bay.

Rescuers had fingers crossed they would still turn around on the high tide but were preparing for the worst.

Lamason said they would not have another chance to refloat the whales until tomorrow's high tide as it was too dangerous to try a rescue at night.

416 whales stranded at Farewell Spit, with about 75 per cent dying before rescue efforts could start. Tim Cuff

In the meantime volunteers would help DOC staff care for the stranded whales throughout the afternoon and do whatever they could to keep them comfortable, he said.

Project Jonah has issued a Facebook alert about the mass stranding at the northern end of Golden Bay. Hundreds of people have responded to the call for volunteers and the road to the South Island beach is packed with cars heading to the remote area.

Project Jonah said 75 per cent of the whales were dead when rescuers arrived at first light.

Rescue efforts were focusing on refloating the remaining 100 live whales at high tide, which was at 10.30am.

Some of those that survived the night stranding were already able to swim on their own.

DOC spokesman Mike Ogle said the whales had stranded on the inside beach of Farewell Spit, 1km from Triangle Flat, near Puponga.

Ogle urged as many fit and competent people as possible to help refloat the surviving whales.

Those helping in the rescue were also told to come prepared with wetsuits, food and water.

Project Jonah general manager Darren Grover said he was told last night a large pod of pilot whales had been spotted close to shore and it was feared they may beach overnight.

"We were told by DOC there may well be whales on the beach this morning."

A team of up to 30 trained medics were headed to the stranding and the call had gone out for volunteers across the region to help.

Specialists from Massey University would be doing necropsies on some of the dead whales later today.

It's the third largest recorded whale stranding in New Zealand since the 1800s. A thousand whales were stranded on the Chatham Islands in 1918 and 450 in Auckland in 1985.

Six years ago 70 pilot whales stranded on Farewell Spit, also in February. The whales, which became separated from their pod, were successfully refloated.

In December 2006, 140 pilot whales stranded at Puponga Bay. Most were saved.